Answers
One question, one straight answer
57 questions, one page each, answered in a few hundred words rather than at the foot of a ranking. Where the honest answer is that the figure printed on the box was measured under conditions the box does not name, this site says that instead of ranking it.
Choosing
How each family differs, what a first purchase should cover, and which half of this site a given problem belongs to.
Compatibility & fit
Mounts, filter diameters in millimetres, tripod thread sizes, shoe types and plate standards — the published figures that decide whether a part joins what you already own.
Focal length & coverage
What the millimetres engraved on a barrel mean in front of one sensor size or another, and why an equivalent figure is arithmetic rather than a measurement.
Aperture & light
Why a zoom quoted f/3.5-6.3 is two apertures and not one, and which end of that pair decides what the lens can still do at dusk.
Flash output & sync
Guide numbers, watt-seconds and sync speeds: three published figures that describe different things, none of which is the light landing on a subject.
Stabilisation & sharpness
What a stop of stabilisation is measured against, which protocol a maker names beside the number, and what happens when none is named.
Support & load
A declared maximum load is a static figure. What it covers, what it says nothing about, and how a head is rated separately from the legs beneath it.
Sensors & formats
Sensor sizes and their names, what a pixel count does and does not settle, and where a crop mode takes its picture from.
Power & media
Stated shot counts and the standard behind them, spare capacity in watt-hours, mains adapters, and which card slots a body publishes.
Colour & white balance
What a colour temperature in kelvin describes, what a rendering index does, and how a neutral reference takes guesswork out of a set.
Weather & protection
Sealing claims and the codes that carry them, which makers publish an ingress rating and which describe the weather in words instead.
Setup & firmware
Bringing a body up, what a maker publishes about updates, and how long that support is stated to run.
When it goes wrong
Frames that come back soft, autofocus that hunts, a flash that fires into a half-black picture.